In a friction-welding process, such as conventional spin-welding process, the components to be welded or fused are placed adjacently to each other and then rotated at a high relative rate of speed in conjunction with an applied axial clamping force. The frictional heating generated at or along a boundary or interface between the components melts a portion of the material, typically plastic or metal, which then flows away from the interface or the “weld zone” in molten form, hereinafter referred to as “molten flash”. When the molten flash cools, a homogenous weld joint is formed at or along the weld zone from the now intermixed materials of the welded components.
Spin-welding provides many advantages, such as relatively short cycle times, large batch sizes, and high overall process efficiency. Spin-welding also provides excellent repeatability when used in conjunction with precise process control methods, i.e., controlled material feed and/or spin rates, axial pressures, applied stroke, etc. However, the bonding strength and long term durability of a weld joint formed via a conventional spin-welding process may be less than optimal when used in conjunction with certain applications, and therefore the spin-welding process is generally restricted or limited to welding relatively small cylindrical parts of similar or like material in order to maximize the strength of the resultant weld joint.